Coaxial cable sometime requires an armor sheath to protect and provide resistance from crushing forces and to prevent the cable from twisting and bending. These armor sheaths are generally flexible yet rigid in the transverse plane to ensure protection against crush resistance and provide resistance to torsion. An example of a coaxial transmission line with an armor sheath is described in U.S. Pat. No. 4,731,502. This patent teaches the use of a helically-wound metallic armor sheath having interlocking edges and grooves between its joint to protect the microwave coaxial transmission line.
While these protective sheaths provide increased protection to the overall cable, in certain situations during construction, the center conductor and inner layers of the coaxial may be altered in length due to elongation or compression causing an unsatisfactory fit between the cable and the armor sheath and undesirable stresses to the cable. As a result, the length of armor sheath must then be modified to compensate for changes in length of the inner cable layers. This often requires correction by trial and error.
FIG. 1 illustrates an existing solution to compensate for changes in length to protect the inner layers by use of a wedge shaped restrainer. This restrainer protects the layers from stresses while the armor sheath is constructed around the cable. FIG. 1 shows a cross-section of an existing connector assembly used for armor-protected cable. A cone shaped restrainer 1 holds the center conductor and insulation 3, inner braid 9, and outer conducting foil 15 within restraining bushing 7. The bushing has a tapered bore to receive the restrainer 1. A layer of outer braid 21 surrounding the armored cable 11 is brazed in the counterbored region 19 of the bushing with the aid of solder preform 13, made of a material such as AWS classification BA9-24 silver brazing alloy. In this application removal of the cable from the armor is no longer possible. It is often desirable to remove the cable from the armor for repair or replacement. In this application, a weakness exists in region 17 since the braided layer 9 is separated from the remainder of the inner construction. It is at this point that any change in length between the armor and cable are absorbed usually at the expense of disturbance of the outer conducting foil 15.
A further complication is that the tapered regions of the restrainer 1 and bushings 7 are more costly to manufacture than straight sections, especially in this case since the inner and outer tapers must match precisely to perform properly.
There is a need for a means for compensating an undesirable differential in the length of a protective armor sheath with respect to the cable it is protecting. There is also a need for a means for removing a cable from its protective armor sheath in order to repair or replace the cable.